There is increasing demand in the oil and gas industry to develop equipment and methods to enable subsea riser repair. Often, the aging risers to be repaired are disposed in deep water, making them inaccessible to divers. Furthermore, increasing restrictions on the use of divers is making riser repair, even in shallow water, increasingly challenging. Thus efforts are being made to develop techniques for deep water riser repair, utilizing apparatuses which can be hydraulically controlled from a remotely operated vehicle (ROV). The techniques must by design also be sensitive to the often fragile nature of the risers, as well as incorporating contingency measures in the event of a failed repair effort.